public struct point
        {
           public int x, y;
            public char c;
        };

point[,] arr = new point[3, 3];
            arr[0, 0].x = 40;
            arr[0, 0].y = 40;
            arr[0, 0].c = 'R';

            arr[0, 1].x = 60;
            arr[0, 1].y = 40;
            arr[0, 1].c = 'R';

            arr[0, 2].x = 100;
            arr[0, 2].y = 40;
            arr[0, 2].c = 'R';

            arr[1, 2].x = 100;
            arr[1, 2].y = 60;
            arr[1, 2].c = 'R';


            arr[2, 2].x = 100;
            arr[2, 2].y = 100;
            arr[2, 2].c = 'R';


            Graphics g = this.CreateGraphics();
            Pen p = new Pen(Brushes.BlueViolet, 13);
            float x1, x2, y1, y2;


            for(int i=0;i<3;i++)
            {
                for(int j=0;j<3;j++)
                {
                    if(arr[i, j].c == '-')
                    {
                        continue;
                    }

                    x1 = arr[i, j].x; x2 = arr[i, j].x; y1 = arr[i, j].y; y2 = arr[i, j].y;
                    int temp_i = i, temp_j = j;
                    while (true)
                    {
                        if (temp_i < 3 && temp_j + 1 < 3)
                        {
                            if (arr[temp_i, temp_j + 1].c == 'R')
                            {
                                x2++;
                                temp_j++;
                                arr[temp_i, temp_j].c = '-';
                                g.DrawLine(p, x1, y1, x2, y2);
                                Thread.Sleep(5);
                            }
                        }

                        else if (temp_i + 1 < 3 && temp_j < 3)
                        {
                            if (arr[temp_i + 1, temp_j].c == 'R')
                            {
                                y2--;
                                temp_i++;
                                arr[temp_i, temp_j].c = '-';
                                g.DrawLine(p, x1, y1, x2, y2);
                                Thread.Sleep(5);
                            }
                        }
                        else if (temp_i < 3 && temp_j - 1 < 3)
                        {
                            if (arr[temp_i, temp_j - 1].c == 'R')
                            {
                                x2--;
                                temp_j--;
                                arr[temp_i, temp_j].c = '-';
                                g.DrawLine(p, x1, y1, x2, y2);
                                Thread.Sleep(5);
                            }
                        }
                        else if (temp_i - 1 < 3 && temp_j < 3)
                        {
                            if (arr[temp_i - 1, temp_j].c == 'R')
                            {
                                y2++;
                                temp_i--;
                                arr[temp_i, temp_j].c = '-';
                                g.DrawLine(p, x1, y1, x2, y2);
                                Thread.Sleep(5);
                            }
                        }
                        else
                        {
                            break;
                        }

                    }
                    break;
                }
            }